/Engine/Source/Runtime/Engine/Public/SaveGameSystem.h
(Optional) initialise the save system for the given user. Useful if the platform may display UI on first use - this can be called as part of the user login flow, for example. If this is not used, any UI may be displayed on the first use of the other save api functions
virtual void InitAsync ( bool bAttemptToUseUI, [FPlatformUserId](API\Runtime\Core\Misc\FPlatformUserId) PlatformUserId, [FSaveGameAsyncInitCompleteCallback](API\Runtime\Engine\ISaveGameSystem\FSaveGameAsyncInitCompleteCallba-) Callback )